The elaboration of a series of aryl iodides into heterocyclic hydroxamates proceeds in good to excellent yield in a palladium catalysed termolecular cascade reaction involving carbon monoxide and protected hydroxylamines. Deprotection affords a range of novel heterocyclic hydroxamic acids. In a related process, N-benzyloxyimides were synthesised in a pentamolecular cascade. The hydroxamic acids were also synthesised using resin-bound hydroxylamine derivatives in a solid-phase cascade process.